By 22 February it was evident that the epidemic was starting in Italy. Already by this time is was known from the experience in China that elderly people were/are especially at risk from this virus. 
By 22 February it was known that – unless the UK closed its borders, which it wasn’t going to do – the virus would arrive in the UK.
The UK did not lock down until 23 March. Even then, as far as I know, Care Homes (for elderly people) were not secured. By secured I mean absolutely sealed so that there was/is no possibility of transmission; which would preclude staff working in the care home and then going home in the evenings.
Had the simple step of sealing off care homes been taken by the beginning of March thousands of people who had every right to live would not have died. (The actual figures for people who have died in care are substantially higher than the government’s figures).  It was absolutely obvious that without specific preventative measures there would be a holocaust in care homes. People pay taxes for well-paid people to carry out all sorts of planning exercises – including for pandemics. Even without any prior planning it required nothing more than the ability to connect 3 glaringly obvious dots (epidemic soon to arrive in the UK, elderly people most at risk, transmission possible via various routes into care homes) to see what would happen if care homes were not sealed off. And that in itself is a very simple step. Why was this not done? And why even now has it not been completely done? (The linked article  below cites shortages of protective equipment and tests. The article at  suggests that there are still routes for people to enter care homes with the virus – even apart from staff who, apparently, can come and go in their cars and see their families).
There is something very very weird in this. A huge amount of huff and puff about the tragedy – but a very simple step of absolutely sealing off care homes and thus protecting thousands of vulnerable elderly people – was not done and, as far as I can tell, still has not been.
- This data (see link) was available by 28 February – but certainly the underlying information that elderly people were especially at risk must have been available before this date.